With the L300 on the SRM-323S I listen at about 2.5 nominally, 3 MAX.
Yup, I listen to my Stax at 3 on my 353X.
My X-00's I listen to at a bit less than 9 O'clock on my Jotunheim (high gain).
On both, for quick 1-song rock out sessions. the volume knob goes to 50%.